The present disclosure relates to a light emitting diode (LED) driving apparatus for driving an LED and an LED lighting apparatus for driving an LED lighting element.
An LED is a semiconductor device formed to have a p-n junction structure to emit light due to the recombination of electrons and holes and is used in a range of fields in line with recent advances in semiconductor technology.
In particular, since LEDs have high efficiency and long lifespan and are environmentally friendly, as compared with existing light emitting devices; fields of application thereof are being extended.
In general, an LED may be driven by applying DC power having a level of a few volts due to the structural nature thereof, and thus, in general, in order to drive an LED with commercial alternating current (AC) power available domestically, commercially, industrially, or the like, an additional means is required.
In order to drive an LED with commercial AC power, an LED driving apparatus typically includes a rectifying circuit, an alternating current-direct current (AC-DC) converter, and the like.
However, a general AC-DC converter is relatively voluminous and may consume a large amount of power, such that the application of the general AC-DC converter to the LED driving apparatus severely offsets advantages of the LED such as high efficiency, a small packaging size, a long life span, or the like.
Thus, recently, research into a device able to directly drive an LED with AC power, without using an AC-DC converter, has been actively conducted.
In the case of an AC direct driving scheme of directly driving an LED with AC power, a smoothing capacitor is not used, and thus, an LED driving circuit is advantageous in terms of a lifespan, a size, and the like thereof.
In a case in which an LED is directly driven with AC power without using an AC-DC converter, a plurality of switches are connected to a plurality of LEDs, respectively, and a corresponding LED group is turned on and off to be driven according to a level of AC power.
Namely, in an LED driving circuit based on the AC direct driving scheme, an LED group may be controlled to be turned on and off according to a change in a voltage level of the AC power.
Meanwhile, in the LED driving apparatus based on the AC direct driving scheme, a turning on/off operation may be automatically adjusted by detecting a current flowing in an LED and controlling the current to follow a reference voltage, and here, since resistors are connected to individual LEDs, a circuit area and manufacturing costs are increased.
Patent Documents 1 and 2 do not employ a configuration for resolving limitations that a circuit area and manufacturing costs are increased due to resistors connected to respective LEDs.